The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
An aircraft is propelled by one or several propulsion assemblies, each comprising a turbojet engine housed in a substantially tubular nacelle. Each propulsion assembly is attached to the aircraft by a mast, usually located under a wing or at the aircraft fuselage.
In general, a nacelle has a substantially tubular structure surrounding the turbojet engine and comprises an air inlet upstream of the engine, a median section intended to surround a fan of said turbojet engine, and a downstream section surrounding the combustion chamber of the turbojet engine, which can be equipped with thrust reversal means.
On the one hand, the air inlet comprises an inlet lip adapted to allow the optimal uptake into the turbojet engine of the air necessary for powering the fan and the inner compressors of the turbojet engine and on the other hand, a downstream structure whereon the lip is brought and intended to channel the air properly, towards the fan vanes. The assembly is attached upstream of a fan casing, belonging to the median section of the assembly.
In flight, according to temperature, pressure and humidity conditions, ice may appear on the nacelle, particularly at the outer surface of the air inlet lip. The presence of ice or frost changes the aerodynamic properties of the air intake and disturbs the air conveyance towards the fan.
A solution to de-ice or deglaze the outer surface is to prevent the formation of ice on this outer surface, by keeping the concerned surface at sufficient temperature.
Thus, it is known for example from document U.S. Pat. No. 4,688,757, to take hot air at the compressor of the turbojet engine and bring it at the air inlet lip in order to heat the walls. However, such a device requires a system of hot air inlet ducts between the turbojet engine and the air inlet, as well as a system for discharging the hot air at the air inlet lip. This increases the mass of the propulsion assembly, which is not required. These drawbacks can be overcome by resorting to electric de-icing systems.
It can be particularly cited document EP 1 495 963 although several other documents relate to the electric de-icing and its developments.
The implementation of an electric de-icing device needs the use of heaters, also called heating carpets, embedded at the air inlet lip adjacent to the outer surface, and electrically powered by a generally three-phased electric power.
A disadvantage of such systems is that they are located in a nacelle area that is particularly exposed to the most severe direct effects of lightning. This leads to induced currents in the device and heating carpets which are particularly high. These induced currents are propagated through the system power harness and may severely damage the system equipment.